Present day cable or wire layers include engine driven machines that have an oscillating blade that penetrates the ground to a predetermined depth while the machine is driven forward to feed the wire or cable into the ground. Examples of such machines are those shown in U.S. Pat. Nos. 3,201,944 and 4,685,832.
Other wire and cable laying devices are known in which a plow is drawn or forced through the ground to open a trench into which a cable or wire is laid. An example of such a device is shown in U.S. Pat. No. 3,066,491 and in U.S. Pat. No. 781,568.
U.S. Pat. No. 5,174,686 discloses a pipe laying machine having a cutter wheel that digs a trench. A blade mounted water jet is provided to form path within a slit formed by the cutter into which a length of pipe is placed.
The engine driven machines of the '944 and '832 patents that include a vibrating arm are better adapted to soil conditions that do not have obstructions in the path of the machine. If such obstructions or other impediments such as roots are present the machine may have to be removed from the trench and the obstruction removed to clear a path for the oscillating blade to form the path for laying the cable.
The manually operated devices shown in the '491 and '568 patents require two separate trenching components. The first component is a small diameter wheel that forms a shallow depression in the ground surface. The shallow depression is then opened up by a plow member that forms a furrow defining a trench. As in the case of the engine driven machines, such devices are difficult to use in soil conditions that include obstructions such as roots or debris.
The special pipe laying machine shown in the '686 patent does not disclose or suggest a cable laying attachment system for use with engine powered tillers that include a carbide tipped saw blade for forming a full depth trench and that will cut through obstructions so as to obviate the need for removing and repositioning a cable laying implement to clear the obstruction.